The invention relates to an apparatus and method for transferring articles into cases using continuous motion, and particularly, where the continuous motion is basically circular and at higher transfer speeds with a small footprint in which case flap tab-lock slitting and flap sealing may also be accomplished.
In the art of case packing, large numbers of articles must be grouped and packaged rapidly by an apparatus that will function dependably without damage to the articles processed. Case packing apparatus has been generally categorized as either intermittent case packing or continuous case packing. In intermittent case packing the article flow and/or case flow is interrupted during article pick up and/or release. Most recently, attention has been directed to continuous case packing in order to increase production. However, the continuous case packing has brought increased problems with handling the processed articles without breakage, damage, or interruption.
In the continuous case packing apparatus, articles are grouped together in successive slugs or groups at a pick up position. The slugs are typically picked up at the pick up position by article grippers carried by an orbital handling machine rotating about two vertical axes. The slugs are transferred to a case loading position where the grippers release the slug of articles into a case. The articles can be released either simultaneously or sequentially as the case is conveyed beneath the slug of articles. Apparatus of this type may be either of the “drop packer” type or “placement packer type.” In the drop packer type, the articles are allowed to drop at least a small distance into the case after release. In the placement packer type, the drop, if any, is minimal and the articles are essentially placed gently onto the bottom of the case.
Continuous motion machines rotating about a single horizontal axis are shown in U.S. Pat. Nos. 5,375,395, 5,257,888, and 5,313,764 using articulating arms and pickup heads. A set of article grippers is carried on the ends of the articulating arms. However, during the angular descent from the pick up position to the case packing position, both horizontal and vertical accelerations are typically encountered by the articles, which are gripped only at their tops or necks. Intermittent circular machines rotating about a single vertical axis are shown in U.S. Pat. Nos. 3,780,492 and 2,807,125.
Various other case packers, generally of the continuous motion type, using a vertical orbital conveyor are shown in U.S. Pat. Nos. 5,212,930, 4,541,524, and 4,294,057. The first patent shows depositing the articles sequentially and individually, rather than as a group or slug, into partitioned cases without positively gripping the articles. The latter two patents use gripper devices to grip and place the articles. U.S. Pat. No. 4,457,121 discloses a continuous motion bottle packer wherein a plurality of grids are mounted individually on spokes of a vertical wheel so that each grid moves through an article in feed position where groups of articles are fed into the grid without interrupting the forward speed. Angular and horizontal accelerations of the articles and their contents are encountered due to the rotary wheel motion during the transfer which may be detrimental to the article and/or contents.
Continuous case packers are also known in which a horizontal rotary carousel is used to move vertically reciprocating gripper sets in a horizontal plane about two vertical axes. The reciprocating gripper sets pick up a slug of articles at one position and transfer the slug of articles to a second position where the gripper set is lowered to deposit the articles into a case. Typically the pickup and release stations are on opposite sides of the carousel, requiring parallel conveyors on each side. However, the disposition of the rotary carousel in a horizontal plane requires an inconvenient floor layout, which also occupies a large amount of floor space. The parallel conveyor arrangements needed for the in feed and out feed of articles adds to the floor space problem. The path of the gripper sets between the slug pick up position and the case packing position is also typically curved producing angular and acceleration forces on the articles. The curved article transfer path intersects the path of the conveyed case only for a brief interval making timing a factor. In various of the rotary carousel types, it is known to deposit the articles by lowering the articles, already gripped by the gripper set, through resilient fingers that guide the articles into partitioned cases.
Case packers, generally of the intermittent type, are shown in U.S. Pat. Nos. 3,553,932 and 3,505,787 which also discloses using combinations of a lifting head having suction cups and bottle grids having pockets for picking up containers and depositing them into cases. The containers and the cases are conveyed on parallel conveyors rather than in-line conveyors, and the transfer from the pick up position to the case loading position is lateral, or transverse, to the flow of containers and cases. U.S. Pat. No. 2,277,688 discloses another case packer using an arrangement of a gripper set and a bottle guide set to package the containers into a case. These types of case packers are generally non-continuous as compared to the continuous motion in-line transfer case packers described above where neither the flow of articles nor the flow of the cases is interrupted during operation of the packer.
The articles are packed in cases which typically have flaps held flush to the sides of the case by tab-locks so the flaps do not interfere with case conveyance. After the case is packed, it is necessary to slit the tab-locks so the flaps can be folded over the top of the case and sealed. Typically, the packed cases with locked flaps are conveyed from the case packer to a transfer location a distance from the case packer. At the transfer location, the cases are metered onto a main flight chain through a slitting section and a sealing section. The metering conveyor and slitting and sealing sections normally require an additional 50 feet of floor space.
The case flap slitting and sealer mechanisms have been long known in the industry for slitting the tab-locks holding the case flaps to the side of the case. These mechanisms, such as manufactured by Standard Knapp, Inc. of Portland, Conn., comprise an independent mechanism generally formed along a separate conveyor downstream from the case packer. In practice, filled cases are removed from the packing apparatus and delivered in an inclined fashion to the slitting and sealing mechanism. The space required is substantially equal that of the packing apparatus. The equipment and operation cost is also substantially equal that of the packing apparatus.
Accordingly, an object of the invention is to provide a continuous case packing apparatus having a characteristic radial motion with case flap separation and flap closure sections combined with the case packing apparatus and process.
Another object of the invention is to provide a continuous motion apparatus and method which moves in a circular or radial motion to provide high speeds of operation for case packing and flap closure and sealing.
Another object of the invention is to provide a continuous, radial motion case packing apparatus and method which rotates about a single, central axis to provide a small footprint and high-speed operation in which case packing and flap closure are carried out.
Another object of the invention is to provide a continuous, radial motion case packing and flap closure apparatus and method in which groups of articles are picked up at a pickup station and transferred to a case packing and flap separation station where the motion of the pickup heads is converted from a radial motion to a substantially straight-line motion during article pickup to align with the articles and during tab-lock slitting to guide the cases.
Still another object of the invention is to provide a continuous, circular motion case packing and flap closure apparatus and method wherein the articles are picked up by pickup heads rotating in a radial path are inserted into cases transported on a rotating conveyor disposed below the radial path of the pickup heads rotating about the same axis where the flaps are separated and closed prior to exiting the plate.
Still another object of the invention is to provide a case packing and flap closure apparatus and method with a continuous rotary conveyor having a radial transport path for transporting cases through a case delivery station, a case packing and flap closure station, and a case exit section.
Another object of the invention is to provide coordinated case packing, case flap separation by tab-lock slitting and flap sealing during radial transport of the cases.
Yet another object of the invention is to provide a continuous motion apparatus and method in which a revolving conveyor plate moves successive packed cases to tab-lock slitting sections where the flaps of each case are separated from the cases and closed.
Another object of the invention is the provision of a single continuous radial motion apparatus and method which picks up articles arranged into groups using pickup heads rotating continuously in a radial path, deposits the articles into successive cases transported along the same radial path, slits the flap tab-locks for separation, and elevates the case flaps for sealing during travel along the radial path.